When Dad was head of public policy for the Wilderness Society in the early '80s, he affixed a "Swat Watt" bumper-sticker to our Volvo... I asked who James Watt was and why we needed to swat him and thus began my education in the interplay between politics and the environment... a discourse that has essentially continued to this day. In litigating the Watt EPA, founding the Grand Canyon Trust, leading the Nature Conservancy's pioneering program in China, and brokering the largest public/private purchase of timber holdings for conservancy in U.S. history or working with private equity titans to audit the environmental impact of their investments to increase both their sustainability and their returns, Dad's essential accomplishment, along with other leading advocates of his generation, has been to infuse hard-nosed professionalism and legal acumen into a movement that had previously been anchored in emotional appeal from the days of John Muir through to David Brower.

Dad's career spans an era that has seen the strategy of fighting for the 'intrinsic spiritual value of nature' give way to making the 'bottom line' argument that we have to accurately account for the value of natural resources in our global economy and confront the economic consequences of destruction of ecosystems and loss of biodiversity. In the face of the needs of 7 billion people, this might now have to be acknowledged as the only argument that stands us a chance of saving the planet anymore. This also happens to be the moment that Dad's generation is passing the baton to mine and it doesn't seem too dramatic to suggest that what we do with it in the next 40 years is going to define the next era of human experience on Earth.

I think that every generation is called in different ways to a higher purpose and is forced to realize that the Great Challenge of an era will identify itself; we don't get to choose it. My grandparent's generation certainly had other plans when they rose and faced the great battles against fascism and totalitarianism; my parents' generation sacrificed care-free youth to carry the torch of civil rights and social equality.

I'm 42 years old. I have little doubt that the legacy of my generation and likely the next will hinge on how we responded to the revelation that we were altering the natural systems of this planet in ways that could not sustain our civilization. The geo-political realities of our moment and all of our domestic social arguments are going to seem like minor squabbles to future generations facing the massive destabilizations that we're queuing up for them with our heedless degradation of the global environment. Whether our great-great grandchildren look at us as wise or as latter-day Nero's, fiddling while the planet burned, is a fate that's going to be decided by what we do in the second Century of the environmental movement.

I feel fairly confident in saying that my generation and even those younger than us have accepted this as our cause and that we are ready to rise to the challenge. And by that I don't mean just the small acts of using CFL's and biodegradable soaps and less plastic. I mean that we understand and are prepared to pay the true long-term costs of overhauling the basic infrastructure of how we live. But we face a daunting reality, which is that all the activism of the last 50 years has not stopped the juggernaut of environmental degradation and climate change and all of the righteous advocacy of the next 50 will still not meet the scale of this challenge unless bold action is taken by political leadership.

Let's say this bluntly: We need a national, bi-partisan commitment to legislation curbing carbon emissions here at home and we need it to have teeth and we need it immediately. And we need to invest in an American technological future that operates sustainably within the natural systems that support our lives.

This isn't about tree-hugging and fish-kissing anymore, it's about the way we live. In the housing sector alone, a federal investment of $5 billion a year over 10 years to 'greening' our housing stock could deliver huge benefits across the board: 25-40 percent energy savings in up to 25 million residential units, up to 50 million tons of carbon dioxide emissions avoided and hundreds of thousands of green jobs created annually when fully implemented.

Such a federal commitment is relatively modest when one considers that HUD currently spends more than $4 billion annually to pay utilities in inefficient government-assisted properties.

The point is that solutions are available but there has been faint political will and now there is no more time for small scale, incremental progress. Policymakers must act with urgency and seriousness of purpose. For starters, Congress simply should not continue to allow taxpayer funds to support building of any kind that does not meet a more demanding minimum standard for energy efficiency and lower carbon emissions.

These are policy decisions that should be easy...they transcend partisan economic philosophies and achieve that rare benchmark of true common sense.

International agreements like the Convention on Biodiversity are important too. Cynics could say these are gestural or bureaucratic or difficult to enforce... but the world community can't get serious about addressing a problem unless that problem is defined, acknowledged and solutions are outlined. How much time have we wasted failing to address climate change just trying to get our leaders to acknowledge the fact that it is happening? Leadership means facing difficult realities and committing to the sacrifices entailed in addressing them. The United States is one of only 3 countries in the United Nations that is not a signatory to the Convention on Biodiversity, having failed to ratify President Clinton's commitment. That's not leadership.

Grassroots action matters too. Earth Day is important because it's about waking up more people to this challenge and committing to engage in it more deeply ourselves. Power in numbers is real, and when we take collective action it matters. We can affect things with daily choices like the products we buy, we can affect things with our votes and we can also affect the pace of change by directly supporting the many terrific organizations working for environmental health.

My partners and I at CrowdRise have set up this fundraising Challenge where you can read all about dozens of the organizations working for the cause of defending the Earth, with all its miraculous life and incredible systems, and a small contribution will help some of them win a total of $50,000 in support from our pals at Groupon.

Martin Luther King spoke famously of 'the urgency of now' but his next words were equally profound. He said: